1. Field of the Invention
The present invention relates to an aerogel composite and a preparation method thereof, more precisely a high performance aerogel composite having various shapes and a preparation method of the same.
2. Description of the Related Art
Aerogel is a super-porous silica material that has a porosity of at least 90% and a pore size of 1˜50 nm. In particular, the heat insulation property of aerogel is superior to any conventional insulating material, so that it is now in the spotlight as a next generation insulating material. Aerogel that is on the market as an insulating material is divided largely into two categories according to the morphology; which are aerogel monolith/powder and aerogel blanket/composite. Silica aerogel monolith has excellent properties such as super-porosity and has a very low thermal conductivity but the mechanical strength thereof is very weak, because of which it is limited in use. Particularly, aerogel powder is not easy to handle because it is very light. The aerogel powder has a very weak mechanical strength and has a hydrophobic property, which means it does not go well with water and accordingly cannot be easily mixed with other materials. Therefore, the aerogel powder is hard to be prepared as a composite and a board. Recently, studies have been going on to process aerogel as a fiber and aerogel mixed composite in order to make up the weakness of aerogel and to process aerogel in many different forms.
In the structure of the aerogel blanket or composite, fibers constitute a major matrix and aerogels are contained between them. When the aerogel blanket or composite is prepared with a low density for flexibility, it would be easily bended or folded, displaying excellent workability. Therefore, it can be applied in pipes or complicated parts for insulation. In the meantime, the aerogel blanket or composite can be processed as a high density product, and is widely used as an insulating material and an absorption material in the fields of construction, industry, and shipbuilding. In the aerogel blanket or composite, the major matrix fiber gives flexibility and mechanical strength to the composite and the aerogel staying in between fibers gives insulating property due to its own superporosity. The aerogel blanket or composite is the product prepared by combining advantageous the characteristics of fiber and aerogel and by reducing disadvantages thereof.
According to the conventional preparation method of aerogel blanket, the thickness, length, density, and shape of the woven fiber used in the blanket are limited. As an example, in the aerogel composite preparation method described in U.S. Patent Publication No. U.S. 2014/0273701, the aerogel finished with drying process is combined with non-woven fiber, so that the aerogel drying process is required twice, which might damage the insulation performance of aerogel. Moreover, in order to combine aerogel as dispersed in water with non-woven fiber, a surfactant is required to make the surface of aerogel to be absorbable, indicating that it is necessary to change the characteristics of the surface of aerogel so that the hydrophobicity of aerogel is reduced. Another problem is the difficulty of mixing because the dried aerogel powder is hard to be dispersed in a solution.